Amat Gotchi

You need to get all the TamaTomo stamps for different characters, I believe, before the first travel destination shows up. According to the Tamagotchi Wikia,

There is a new travel destination layout. The first unlockable destination is unlocked by getting all the happy symbols for the first generation, and the fourth destination is Henshin Jo, where your character can transform to its Henshin Jo version. There is a destination called Gotchi King's Castle which is similar to Concert Hall, but has some new songs.